package edu.mit.csail.sls.wami.util;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.StringWriter;

import javax.servlet.http.HttpServletRequest;

public class ServletUtils {

	public static void sendStream(InputStream in, OutputStream out)
			throws IOException {
		sendStream(in, out, 2048);
	}

	public static void sendStream(InputStream is, OutputStream os, int bufsize)
			throws IOException {
		byte[] buf = new byte[bufsize];
		int n;
		while ((n = is.read(buf)) > 0) {
			// System.out.println("Sending bytes: " + n);
			os.write(buf, 0, n);
		}
	}

	public static String convertStreamToString(InputStream is) {
		BufferedReader reader = new BufferedReader(new InputStreamReader(is));
		StringBuilder sb = new StringBuilder();

		String line = null;
		try {
			while ((line = reader.readLine()) != null) {
				sb.append(line + "\n");
			}
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			try {
				is.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}

		return sb.toString();
	}

	public static String getClientAddress(HttpServletRequest request) {
		String clientAddress = request.getRemoteAddr();

		String forwardedFor = request.getHeader("x-forwarded-for");
		if (forwardedFor != null) {
			clientAddress = forwardedFor;
		}

		return clientAddress;
	}

	final static String[] hex = { "%00", "%01", "%02", "%03", "%04", "%05",
			"%06", "%07", "%08", "%09", "%0a", "%0b", "%0c", "%0d", "%0e",
			"%0f", "%10", "%11", "%12", "%13", "%14", "%15", "%16", "%17",
			"%18", "%19", "%1a", "%1b", "%1c", "%1d", "%1e", "%1f", "%20",
			"%21", "%22", "%23", "%24", "%25", "%26", "%27", "%28", "%29",
			"%2a", "%2b", "%2c", "%2d", "%2e", "%2f", "%30", "%31", "%32",
			"%33", "%34", "%35", "%36", "%37", "%38", "%39", "%3a", "%3b",
			"%3c", "%3d", "%3e", "%3f", "%40", "%41", "%42", "%43", "%44",
			"%45", "%46", "%47", "%48", "%49", "%4a", "%4b", "%4c", "%4d",
			"%4e", "%4f", "%50", "%51", "%52", "%53", "%54", "%55", "%56",
			"%57", "%58", "%59", "%5a", "%5b", "%5c", "%5d", "%5e", "%5f",
			"%60", "%61", "%62", "%63", "%64", "%65", "%66", "%67", "%68",
			"%69", "%6a", "%6b", "%6c", "%6d", "%6e", "%6f", "%70", "%71",
			"%72", "%73", "%74", "%75", "%76", "%77", "%78", "%79", "%7a",
			"%7b", "%7c", "%7d", "%7e", "%7f", "%80", "%81", "%82", "%83",
			"%84", "%85", "%86", "%87", "%88", "%89", "%8a", "%8b", "%8c",
			"%8d", "%8e", "%8f", "%90", "%91", "%92", "%93", "%94", "%95",
			"%96", "%97", "%98", "%99", "%9a", "%9b", "%9c", "%9d", "%9e",
			"%9f", "%a0", "%a1", "%a2", "%a3", "%a4", "%a5", "%a6", "%a7",
			"%a8", "%a9", "%aa", "%ab", "%ac", "%ad", "%ae", "%af", "%b0",
			"%b1", "%b2", "%b3", "%b4", "%b5", "%b6", "%b7", "%b8", "%b9",
			"%ba", "%bb", "%bc", "%bd", "%be", "%bf", "%c0", "%c1", "%c2",
			"%c3", "%c4", "%c5", "%c6", "%c7", "%c8", "%c9", "%ca", "%cb",
			"%cc", "%cd", "%ce", "%cf", "%d0", "%d1", "%d2", "%d3", "%d4",
			"%d5", "%d6", "%d7", "%d8", "%d9", "%da", "%db", "%dc", "%dd",
			"%de", "%df", "%e0", "%e1", "%e2", "%e3", "%e4", "%e5", "%e6",
			"%e7", "%e8", "%e9", "%ea", "%eb", "%ec", "%ed", "%ee", "%ef",
			"%f0", "%f1", "%f2", "%f3", "%f4", "%f5", "%f6", "%f7", "%f8",
			"%f9", "%fa", "%fb", "%fc", "%fd", "%fe", "%ff" };

/**
	   * Encode a string to the "x-www-form-urlencoded" form, enhanced
	   * with the UTF-8-in-URL proposal. This is what happens:
	   *
	   * <ul>
	   * <li><p>The ASCII characters 'a' through 'z', 'A' through 'Z',
	   *        and '0' through '9' remain the same.
	   *
	   * <li><p>The unreserved characters - _ . ! ~ * ' ( ) remain the same.
	   *
	   * <li><p>The space character ' ' is converted into a plus sign '+'.
	   *
	   * <li><p>All other ASCII characters are converted into the
	   *        3-character string "%xy", where xy is
	   *        the two-digit hexadecimal representation of the character
	   *        code
	   *
	   * <li><p>All non-ASCII characters are encoded in two steps: first
	   *        to a sequence of 2 or 3 bytes, using the UTF-8 algorithm;
	   *        secondly each of these bytes is encoded as "%xx".
	   * </ul>
	   *
	   * @param s The string to be encoded
	   * @return The encoded string
	   */
	public static String encode(String s) {
		StringBuffer sbuf = new StringBuffer();
		int len = s.length();
		for (int i = 0; i < len; i++) {
			int ch = s.charAt(i);
			if ('A' <= ch && ch <= 'Z') { // 'A'..'Z'
				sbuf.append((char) ch);
			} else if ('a' <= ch && ch <= 'z') { // 'a'..'z'
				sbuf.append((char) ch);
			} else if ('0' <= ch && ch <= '9') { // '0'..'9'
				sbuf.append((char) ch);
			} else if (ch == ' ') { // space
				sbuf.append('+');
			} else if (ch == '-'
					|| ch == '_' // unreserved
					|| ch == '.' || ch == '!' || ch == '~' || ch == '*'
					|| ch == '\'' || ch == '(' || ch == ')') {
				sbuf.append((char) ch);
			} else if (ch <= 0x007f) { // other ASCII
				sbuf.append(hex[ch]);
			} else if (ch <= 0x07FF) { // non-ASCII <= 0x7FF
				sbuf.append(hex[0xc0 | (ch >> 6)]);
				sbuf.append(hex[0x80 | (ch & 0x3F)]);
			} else { // 0x7FF < ch <= 0xFFFF
				sbuf.append(hex[0xe0 | (ch >> 12)]);
				sbuf.append(hex[0x80 | ((ch >> 6) & 0x3F)]);
				sbuf.append(hex[0x80 | (ch & 0x3F)]);
			}
		}
		return sbuf.toString();
	}

	public static String getStackTrace(Throwable e) {
		StringWriter sw = new StringWriter();
		PrintWriter pw = new PrintWriter(sw);
		e.printStackTrace(pw);
		return sw.toString();
	}
}
